Chretien de Troyes was one of the most important medieval writers of Arthurian narrative. A key figure in reshaping the ‘once and future fictions’ of Arthurian story, he was instrumental in the late twelfth-century shift from written and oral legendary traditions to a highly sophisticated literary cultivation of the Old French verse romance. While examining individually each of Chretien’s five Arthurian romances, Donald Maddox looks at their coherence as a group, suggesting that their intertextual relations lend a harmony of meaning and design to the ensemble as a whole. Central to his argument is the focus on customs, which provide unity within as well as among the works while conveying an acute sense of the vulnerability and dissolution of feudal institutions in an age of social crisis and transition.